arm_power_q7.c
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| text/x-c
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CLexer
jeandet@pc-de-jeandet3.LAB-LPP.LOCAL
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r41 | /* ---------------------------------------------------------------------- | ||
| * Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
| * | ||||
| * $Date: 15. July 2011 | ||||
| * $Revision: V1.0.10 | ||||
| * | ||||
| * Project: CMSIS DSP Library | ||||
| * Title: arm_power_q7.c | ||||
| * | ||||
| * Description: Sum of the squares of the elements of a Q7 vector. | ||||
| * | ||||
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | ||||
| * | ||||
| * Version 1.0.10 2011/7/15 | ||||
| * Big Endian support added and Merged M0 and M3/M4 Source code. | ||||
| * | ||||
| * Version 1.0.3 2010/11/29 | ||||
| * Re-organized the CMSIS folders and updated documentation. | ||||
| * | ||||
| * Version 1.0.2 2010/11/11 | ||||
| * Documentation updated. | ||||
| * | ||||
| * Version 1.0.1 2010/10/05 | ||||
| * Production release and review comments incorporated. | ||||
| * | ||||
| * Version 1.0.0 2010/09/20 | ||||
| * Production release and review comments incorporated. | ||||
| * -------------------------------------------------------------------- */ | ||||
| #include "arm_math.h" | ||||
| /** | ||||
| * @ingroup groupStats | ||||
| */ | ||||
| /** | ||||
| * @addtogroup power | ||||
| * @{ | ||||
| */ | ||||
| /** | ||||
| * @brief Sum of the squares of the elements of a Q7 vector. | ||||
| * @param[in] *pSrc points to the input vector | ||||
| * @param[in] blockSize length of the input vector | ||||
| * @param[out] *pResult sum of the squares value returned here | ||||
| * @return none. | ||||
| * | ||||
| * @details | ||||
| * <b>Scaling and Overflow Behavior:</b> | ||||
| * | ||||
| * \par | ||||
| * The function is implemented using a 32-bit internal accumulator. | ||||
| * The input is represented in 1.7 format. | ||||
| * Intermediate multiplication yields a 2.14 format, and this | ||||
| * result is added without saturation to an accumulator in 18.14 format. | ||||
| * With 17 guard bits in the accumulator, there is no risk of overflow, and the | ||||
| * full precision of the intermediate multiplication is preserved. | ||||
| * Finally, the return result is in 18.14 format. | ||||
| * | ||||
| */ | ||||
| void arm_power_q7( | ||||
| q7_t * pSrc, | ||||
| uint32_t blockSize, | ||||
| q31_t * pResult) | ||||
| { | ||||
| q31_t sum = 0; /* Temporary result storage */ | ||||
| q7_t in; /* Temporary variable to store input */ | ||||
| uint32_t blkCnt; /* loop counter */ | ||||
| #ifndef ARM_MATH_CM0 | ||||
| /* Run the below code for Cortex-M4 and Cortex-M3 */ | ||||
| q31_t input1; /* Temporary variable to store packed input */ | ||||
| q15_t in1, in2; /* Temporary variables to store input */ | ||||
| /*loop Unrolling */ | ||||
| blkCnt = blockSize >> 2u; | ||||
| /* First part of the processing with loop unrolling. Compute 4 outputs at a time. | ||||
| ** a second loop below computes the remaining 1 to 3 samples. */ | ||||
| while(blkCnt > 0u) | ||||
| { | ||||
| /* Reading two inputs of pSrc vector and packing */ | ||||
| in1 = (q15_t) * pSrc++; | ||||
| in2 = (q15_t) * pSrc++; | ||||
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); | ||||
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ | ||||
| /* Compute Power and then store the result in a temporary variable, sum. */ | ||||
| sum = __SMLAD(input1, input1, sum); | ||||
| /* Reading two inputs of pSrc vector and packing */ | ||||
| in1 = (q15_t) * pSrc++; | ||||
| in2 = (q15_t) * pSrc++; | ||||
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); | ||||
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ | ||||
| /* Compute Power and then store the result in a temporary variable, sum. */ | ||||
| sum = __SMLAD(input1, input1, sum); | ||||
| /* Decrement the loop counter */ | ||||
| blkCnt--; | ||||
| } | ||||
| /* If the blockSize is not a multiple of 4, compute any remaining output samples here. | ||||
| ** No loop unrolling is used. */ | ||||
| blkCnt = blockSize % 0x4u; | ||||
| #else | ||||
| /* Run the below code for Cortex-M0 */ | ||||
| /* Loop over blockSize number of values */ | ||||
| blkCnt = blockSize; | ||||
| #endif /* #ifndef ARM_MATH_CM0 */ | ||||
| while(blkCnt > 0u) | ||||
| { | ||||
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ | ||||
| /* Compute Power and then store the result in a temporary variable, sum. */ | ||||
| in = *pSrc++; | ||||
| sum += ((q15_t) in * in); | ||||
| /* Decrement the loop counter */ | ||||
| blkCnt--; | ||||
| } | ||||
| /* Store the result in 18.14 format */ | ||||
| *pResult = sum; | ||||
| } | ||||
| /** | ||||
| * @} end of power group | ||||
| */ | ||||